The objective of this research was to test the applicability of using electrical capacitance tomography (ECT) as a rapid, in situ, and non-destructive method to monitor root health and detect disease before visual symptoms present. Two studies were performed. The first study compared capacitance measurements of healthy and stunted tomato plants. ECT measurements showed a slight increase (34%) in capacitance for the stunted group, while the healthy plants displayed a large increase (67%). The second study compared ECT measurements of healthy bell pepper plants and pepper plants exposed to Phytophthora capsici (PCap). The inoculated plants that died showed a sudden spike in capacitance (∼52%) 12-24 hours before wilting and browning of the stem occurred. The healthy plants all showed a greater increase in capacitance compared with inoculated plants that survived for the same monitoring period. The results from the two studies indicate that ECT is a rapid and non-destructive method to monitor root health and detect disease pre-symptomatically.